We propose to develop novel imaging techniques to quantity breast density and breast parenchymal patterns[unreadable] that can be used to further study the linkage of tissue composition and cancer risk.[unreadable] Breast density, as currently defined and measured, is a strong risk factor for breast cancer. The clinical[unreadable] measure of mammographic density is inadequate to study how the composition of breast tissue relates to[unreadable] cancer risk, especially on tissue specimens. We will develop the following: a Dual X-ray Absorptiometry[unreadable] (DXA) technique to quantify breast tissue composition on a clinical digital mammography device and a novel[unreadable] technique to quantify the projected parenchyma pattern using a combination of connectivity (Euler number)[unreadable] and fractal dimensions. These measures will be quantified in whole breast specimens and compared to[unreadable] current clinical measures of breast density (i.e., mammographic density and BI-RADS scores). In addition, we[unreadable] will extend these techniques to their use in thin (5 mm or less) breast tissue sections. Local measures of[unreadable] density and structure will be compared to whole breast measures by sectioning breasts specimens in their[unreadable] entirety and summing the local measures. Lastly, we will study if metabolic profiles measured using magnetic[unreadable] resonance magic angle spectroscopy (MR-MAS) correspond to specific pathological tissue types associated[unreadable] with dense breast (from Project 2) by histology analysis of the same samples.[unreadable] The results of this study may lead to (1) the implementation of new clinical measures of breast composition[unreadable] and risk in clinical mammograms, (2) novel compositional measures of density for thin tissue samples such as[unreadable] biopsy tissue, and (3) the identification of a metabolic signature that is specific to breast tissue type and[unreadable] applicable to new MR spectroscopic imaging techniques for a more sensitive and specific measure of risk.